Telephone calls made by inmates in jails, prisons and other confinement institutions are usually processed using so-called Inmate Calling Services (ICSs). A provider of such services may also be called an Inmate Calling Service, but will here be distinguished, when necessary, by using the term ICS provider. An ICS provider typically employs a variety of processors, databases and other equipment elements individually well known in the art in a system (here referred to as an ICS System or ICS infrastructure) to perform the many functions involved in ICSs. Particular functions, such as call control, three-way call treatment (discussed below) and many others are typically configured and performed under stored program control of such ICS systems.
Institutional regulations typically limit calls from an inmate in terms of call duration, frequency and call destinations for which calls are authorized. Often, a list or computer database is consulted in response to a call request made by an inmate to determine whether the requested call is to an authorized called destination. Such databases provide a called number validation or screening to prevent harassing calls from being made to law enforcement or other government officials, for example, or to seek to prevent conversations relating to criminal activity. In some cases potential called parties indicate that they do not wish to receive calls from a category of callers, such as all callers, or one or more individuals at a particular confinement facility.
Modern technology has provided ample means for inmates and their accomplices to seek to circumvent call destination (called number) limitations. Thus, for example, so-called three-way (3-way) calls may be attempted by seeking to bridge (or conference) an existing (2-way) first call that has been completed from an inmate to an otherwise authorized called party. This second call is placed by or on behalf of the authorized first called party to an unauthorized second called party. In particular cases, the first called party may retain a presence on these bridged first and second calls, or the first called party may hang up the first call after the second called party answers. In the latter case, the call from the inmate will effectively have been forwarded to the second (unauthorized) called party.
Different versions of authorized and encouraged bridging or conferencing of telephone calls are offered by local and long distance telephone companies to provide their subscribers with a rich array of calling services. However, such bridging can be misused when an ICS call to an authorized (first) called party is bridged to another unauthorized (second) called party. For example, bridging may be accomplished by the first called party using a second telephone line at the station set of that first called party to reach (and bridge or conference) the unauthorized second called party. The terms bridge and conference will be used interchangeably in this application unless a distinction is required by a particular context. Some practitioners in the telecommunications arts seek to distinguish extending a call to a third party solely through a telephone company central office, or the equivalent, from a bridge established at a (first) called party station. Call forwarding likewise has several different implementations, some of which involve behavior, such as keying in a prefix (such as 72 #) followed by the forwarded-to number. Moreover, such activation of call forwarding on a telephone line (associated with a subscriber number or account) can often be performed remotely from anywhere a standard dual-tone multi-frequency (DTMF) telephone set can be used to place a call to the telephone company providing such remote call forwarding service. For simplicity in the sequel, all calls involving bridging, conferencing or forwarding of calls to unauthorized parties will be referred to as unauthorized 3-way calls, or simply 3-way calls if no authorization for 3-way calls exists for the relevant context. Similarly, the actions seeking to establish or maintain such calls will be referred to as 3-way call attempts or 3-way calling. It should be understood that a conference, authorized or not, can be sought to be established between more than three parties. Such conference calls will nevertheless be referred to as 3-way calls, unless the context requires that a distinction be made.
ICS providers use specialized call handling equipment to process a request for a call by an inmate to a (first) called party identified by the inmate by temporarily connecting the inmate calling party to ICS infrastructure equipment—effectively placing the inmate calling party on hold. This on-hold condition persists until the conditions (regarding allowability of called parties and validation of numbers to be called, among others) imposed by the institution or the ICS service provider are satisfied and the called party is available to be connected (bridged) with a connection from the ICS infrastructure to the called party. Unauthorized 3-way calls described above are to be distinguished from calls from a calling inmate that are bridged to a call to an authorized first called party and another authorized party. Such authorized 3-way calls may, e.g., include an ICS call to an authorized (first) called party that also includes a bridged call to an authorized attorney. Such authorized 3-way calls are sometimes erroneously identified as unauthorized 3-way calls because of call party errors or because of ICS infrastructure limitations.
Since most calls by inmates using an ICS are collect calls, assent of the called party to accept charges for the call is usually indicated by using keyed DTMF signals. For example, a number, such as 3, is commonly keyed by a called party in response to a voice announcement from the ICS system seeking willingness of a called party to accept and pay for a call received from an inmate. In practice, such voice prompts are played when a called party answers a call from an inmate, but before the inmate is bridged to the connection to the authorized called party. Such voice prompts will typically indicate the nature of the call (a call from a particular jail) and the identification of the calling inmate party, and will typically require that the called party depress one or more identified keys on his/her telephone keypad, e.g., “Please press the three key if you agree to accept this call and have this call charged to your telephone account.” In particular cases, such as when pre-paid, debit and certain free calls may be included in ICS service offerings, other particular language may be used, e.g., “To accept the charges for this call, press 3.” As used in this application, acceptance of the call should be understood to include agreement to pay for the call, unless otherwise stated. Generally, if such acceptance is not received in due course by the ICS provider, the call will be terminated. Alternatively, the voice prompt will be repeated, other voice prompts will be delivered to the called party, or other communication will ensue between the ICS provider and the called party until acceptance is received or the call is terminated.
When the called party accepts an incoming ICS collect call to be charged to his/her account, the connection from the calling inmate to ICS infrastructure is bridged to the connection from the ICS infrastructure to the called party. In typical practice, ICS equipment will record, and a confinement officer or another on behalf of the confinement institution will selectively monitor some or all of: call requests by inmates, voice announcements and prompt(s) from the ICS provider to an authorized called party, called party responses (including DTMF signals received by the ICS provider that signal acceptance of the call). As well, as the telephone conversation between the calling inmate and the called party that occurs after acceptance by the called party will typically be monitored and/or recorded. Of course, any subsequent bridging or forwarding of connections to include the inmate calling party and other than the original called party (and the inmate calling party) will typically be monitored and/or recorded.
Certain signal conditions typically appear on a telephone connection during an attempt by the inmate calling party or someone at the original called station seeking to bridge or conference a third party to an existing call completed from an inmate to an authorized called party. Attempts to thwart, or at least detect, unauthorized 3-way calling have therefore tended to focus on detecting signals arising from activities by an authorized called party in making a 3-way call attempt. Thus, in particular, monitoring of line signals during an on-going connection for the presence of so-called hook-flash signals used by some telephone companies in providing conferencing or call forwarding has been employed. In other attempts at 3-way call detection, other particular telephone line signal conditions have been monitored, such as background noise levels, call progress tones, DTMF dialing tones, and others. However, because communications networks are subject to a variable array of noise conditions and other impairments, and because monitoring equipment and software often prove inadequate to their task, and for other reasons, 3-way call detection efforts have proven inaccurate and largely unsatisfactory. Further, it has proven costly in terms of processing resources needed for continued monitoring of an on-going call for any of a large number of signal conditions possibly indicative of 3-way call attempts.
The incidence of false-positive indications of 3-way call attempts has likewise resulted in the inconvenience of unnecessary call terminations and consequent call expenses to billed parties. Many such false positive determinations of unauthorized 3-way calling activity are attributed to inadvertent keying of one or more digits by a party to an otherwise authorized 2-way call, or to crosstalk of signals from other lines or trunks in the telecommunications plant. Still other false determinations of 3-way calling activity are attributed to a called party subscribing to a call waiting feature that causes a tone to appear on an on-going conversation when an incoming call arrives at an authorized called party location. Still other causes for making determinations of 3-way calling made by some ICS providers are ascribed to use by called parties of cordless phones, wireless phones or by static and interference on a telephone line. Such noise can be of a type that is indistinguishable by current 3-way call detection devices and techniques from a hook-flash signal or other signal condition or conditions used for 3-way call determination.
Certain types of 3-way calling provided by telephone companies require that a first called party put the connection from the ICS infrastructure to that first called party in a hold state, therefore giving rise to speech silence over that connection. Unfortunately, silence resulting from this on-hold state is frequently indistinguishable from silence from other causes. Thus, for example, a first called party using a cordless or wireless telephone might experience a temporary drop-out or significant lowering of sound volume that is tantamount to silence on the line. Also, many conversations between an inmate and family or friends may produce emotional or other circumstances giving rise to long periods of silence. Current ICS infrastructure and methods practiced using such infrastructure are often incapable of distinguishing between different kinds of periods of silence or apparent silence. A result of this is that a judgment can readily be made that a 3-way attempt is being made, often resulting in termination of the call.
As will be apparent from the foregoing, most attempts at dealing with unauthorized 3-way calls are made when an actual or suspected 3-way call is being set up. Call termination is a typical response by many ICS providers if uncertainty remains after some line condition or other behavior of the call parties appears suspicious. The cost and inconvenience of false positive findings is obviously considerable, often disproportionately impacting persons of limited financial means.
Since many ICS calls are subject to a so-called per call operator service charge (nonrecurring charge) or similar charge, e.g., a higher rate for an initial period of a call, however short, the billed party experiencing premature call terminations is required to pay consecutive per call operator service charges when additional calls are required because of such premature call terminations. This is the case when such premature termination occurs because of a false positive determination that unauthorized call activity is transpiring. In some documented cases, a large portion of ICS calls have been found to have suffered premature, and oftentimes erroneous, terminations and have been subject to such repeated per call charges. In what many consider an even more serious consequence of false positive determinations of 3-way call attempts, activities deemed to be a 3-way call attempt (or an actual 3-way call completion) are often treated by an ICS provider or institutional management as justification to limit future calling privileges.
Further, there exists a careful, and often controversial, balance that is sought between the interests of law enforcement officials, criminal investigators, authorized called parties, various advocacy groups and ICS providers relative to false positive determinations of 3-way calls. Technology currently deployed in ICS systems can be configured to be more or less sensitive to various line signal conditions. Such sensitivity can be characterized in terms of one or more thresholds for a variety of respective call behaviors and/or line conditions. Alternatively, some composite metric, e.g., a minimum number of detected DTMF digits and certain defined periods of silence, can be phrased as a threshold. For future purposes in this description, such individual and composite thresholds will be collectively referred to as a threshold.
Determination of an appropriate threshold for these conditions is typically made based on a variety of conditions, including type of network infrastructure, call volume, expenses related to staff for monitoring and evaluation, observed conditions and prior experience with particular threshold values. Some are concerned that expediency will dictate that the threshold will be set too low, thereby causing many not-clearly-defined and/or not-clearly-understood behaviors or line conditions to be treated as positive indications of a 3-way attempt—with the result that an excessive number of premature call terminations occur. Others are concerned that the threshold be set too high to detect only the most certain or most egregious behaviors and line conditions, so that the number of positive indications is low. What is needed is a 3-way call attempt detection and prevention process that is fair and reasonable, as viewed by a broad consensus of those concerned. In particular, when there is sufficient uncertainty as to whether an actual 3-way call attempt is or was made, measures should be taken to reduce that uncertainty. When such uncertainty cannot be reduced to an acceptable level, premature termination of the call by an ICS service provider should not be the only option. Also to be considered are the practical limitations of call processing equipment and processes, the lack of familiarity by some users with ICS procedures, and the ingenuity and past behavior of malicious ICS users.
Only when it can be established with sufficient certainty that, under then-prevailing circumstances, an unauthorized 3-way call attempt has been made—or is in the process of being made—should an ICS service provider unilaterally terminate a call. Further, a default result of treatment of potentially suspicious call party behavior or line signal conditions should not cause undue expense or inconvenience for the call parties.
Interactive voice response (IVR) systems have become ubiquitous in modern commerce. Recorded announcement such as “Please press 1 for sales, 2 for service” and the like are the norm when calling many businesses. Such IVR techniques have been adapted for use in ICS systems, primarily for announcing an incoming call to an authorized called party and receiving a called party assent, e.g., in the form a one or more returned DTMF digit tone signals. Because most ICS systems rely to a great degree on IVR, there is often no immediate recourse for a calling or called party to a premature termination of an on-going ICS call, including those that were the result of a false positive 3-way call determination or an arbitrary decision by an ICS provider to terminate the call.
It is therefore desired that systems and methods be provided for avoiding premature termination of ICS calls because of false positive, or other improper or inappropriate determinations of 3-way call attempts or other suspicious behavior. Techniques for more thorough analysis of the state of on-going ICS calls, signal conditions on such calls, and any inputs or other evidence offered by parties to the ICS call are needed to avoid improper charges (including unnecessary additional call costs), suspension of calling privileges, wasted time and effort—all with little or no recourse by parties to the call. It remains essential, of course, that suppression of those calls that have a high likelihood of being actual 3-way call attempts (or completions) be maintained.